Automatic train-control system



Nov. 15, I 92 7.

WJQHOWE AUTOMATIC TRAIN CONTROL SYSTEM Filed Dec.

MMQ

INVENTUH 74 $4 k W ilk Patented Mgr I PATENT OFFHCE.

UNlTEFD STATES WINTHROP K. HOVJ'E, GE RGCHESTER, NEW YORK, ASSIGNOR 'IOGENERAL RAILW'AY SIGNAL COMPANY, 013 GATES, NEW YGRK, A CORPORATION OFNEW YORK.

AUTOMATIC TBAIN CONTROL SYSTEM.

Application filed December lhis invention relates to systems for au--tomatically controlling the speed of railway trains.

It is desirable that a system for automatically controlling railwaytrains should, for reasons which are quite generally understood andappreciated by those skilled in the art o'r' railway signaling, providefor controlling the speed of a train under conditions where the trainshould proceed cautiously, in obedience to a caution signal, or around acurve, or down a dangerous grade, or the like. Also, such a systemshould preferably be constructed so that the control thereof isaccomplished in accordance with the principles and practices which havebeen found to be safe and economical by long trial and experience, andparticularly in accordance with the general practices in track circuitedblock signaling systems.

Briefly, without attempting to define exactly the scope and nature ofthe invention, it is contemplated according to this invention, to dividethe traclrway for the trains into electrically isolated track circuitedblocks and to provide a suitable controlling ramp or other means foreach block which is adapted to cooperate with a shoe or other devicecarried by the train, so that by the mechanical and electricalcooperation of said shoe with said ramp the information necessary forthe proper operation of the system concerning the traflic conditions ina certain number of blocks ahead can be communicated from the traclnvayto the moving train in a simple and reliable manner. In case the trainshould enter a block in which it should proceed cautiously in obedienceto a caution signal and be prepared to stop at the end of that block,certain mechanism on the train is set into operation to determine thesafe permissive speed for the train at the different points in itstravel through said block; and this mechanism is arranged to cooperatewith a suitable appliance responding to the actual speed of tae train,so that. as said u'icchanism moves and im' poses more and more of alin'iitation on the permissive speed ol the train. determined withregard to the length oi. the block. the braking equipment of the train,the weight of the train, grades and curves in the track and other suchfactors as altect the distance in which the train can be brought to astop 4, 1915. Serial No. 65,9'71.

by its brakes, unless the actual speed of the t am is reduced tocorrespond with the permissive speed prescribed by said mechanism, awarning signal will be given and then subsequently, it this warningsignal is disregarded, the brakes of the train will be automaticallyapplied. It is a well known fact to those skilled in the art of railwaysignaling that, in order to facilitate and expedite tratiic, the blocksare made of varying lengths; and consequently, while said mechanismwhich establishes or determines the pern' issive speed for the trainwill give accurate results for blocks of substantially the same lengthand physical characteristics, this mechanism cannot be used for otherblocks ot a different length without a very appreciable error, with theresult of either unnecessarily delaying traffic, or of failing tocontrol the train with proper safety.

lVith these considerations in view, one of the principal objects of thisinvention is to devise a system for automatically controlling railwaytrains, in which in controlling the speed of the train, due allowanceWill be made for the varying length of the blocks into which thetrackway for the train is divided.

A further object of the invention is to devise a system forautomatically controlling railway trains in which means is providedwhereby the speed of the train may be properly governed irrespective ofthe length of the several blocks over which the train travels.

Other objects and advantages will appear as the description of theinvention progresses, and the novel features of the invention will beparticularly pointed out in the appended claims.

The invention primarily consists i the parts, in the arrangements andcombinations of parts, and in the controlling circuits therefor, whichwill be fully set forth herematter.

In describing the invention in detail, retercucc is had to theaccon'ipanying drawing, in which is illustrated the preferred physicalembodiment of the invention and in which The figure is a diagrammaticillustration of the parts of a system for automatically controlling thespeed of railway trains em bodying the invention, the parts being shownarbitrarily in certain chosen positions considered to be best adaptedfor showing the construction and the electrical connections between theparts rather than .trictly in accordance with their actual construction,arrangement and location, said figure illustrating the parts of thesystem carried on the train and the arrangement of parts and electricalconnections therefor along the trackway.

Referring to the accompanying drawing, one track rail 1 of the trackwayover which the train passes is electrically continuous, the separaterail sections thereof being suitably bonded together: and the othertrack rail 2 is divided by suitable insulating joints 3 into blocks A,B, (l. D and E. These blocks may be of any length necessary to obtainthe desired spacing of the trains;

' but, as pointed out hereinbefore, in practice all of the blocks of aparticular railway will not be of the same length. For the purpose ofrendering more intelligible the features of the construction andoperation of the system embodying this invention. whereby due allowanceis made for the different lengths of the blocks, the block Bis assumedto rcprc sent a short block, the block D a longer block and the block Ca. still longer block.

- It is to be understood that the particular successive occurrence ofthe different length blocks illustrated is not compulsory, since severalblocks of the same length may follow each other, then anynumber oflonger blocks or shorter blocks, and so on in any sequence. The normaldirection of traffic is indicated by the arrow T.

The parts and electrical connections therefor associated with each blockare the same, and for simplicity and clearness said parts and electricalconnections therefor associated with the blocks C and D, will be giventhe salne reference characters as said parts and electrical connectionstherefor associated with the block B, with the distinctive exponents 1?and 2 added thereto.

At one end of each block, preferably the exit end, is a track battery4:. which is connected across the track rails 1 and 2; and at the otherend of each block is a track relay 5 which is connected by conductors 6and 7 across the track rails. The track battery 4 and the track relay 5of each block, together with the track rails 1 and 2 of that block.constitute the well known normally closed track circuit. the operationof which will be clear to those skilled in the art of railway signalingwithout further description. Each track relay 5 has two armatures 8 and9 which are represented in the drawing according to establishedconvention. Adjacent to the entrance to each block is a ramp R which issupported in any suitable way adjacent to one of the track rails and insuch a manner as to be insulated from the track rails. Each ramp R isprovided with suitable controlling circuits by means of which anelectrical difference of potential created by suitable sources ofelectrical energy, as two batteries 10 and 11, may be established attimes between said ramp R and the continuous track rail 1.

Located along the trackway, preferably between the track rails 1 and 2,are suitable selector ramps SR, SC and SL which are located at differentpoints between the track rails 1 and 2 in order to determine theparticular selection obtainable by the particular ramps. These selectorramps act like cams or similar devices for mechanically actuatingcooperating tappets carried by the train, and may be supported in anysuitable way upon the ties of the trackway, preferably resiliently. Theends of the selector ramps gradually slope upwardly so that the tappetscarried by the train may engage said ramps without undue shock; and saidselector ramps may be of any length desired to operate the tappetscarried by the train slowly. Further factors affecting the location andarrangement of the selector ramps will be set forth hereinafter.

The electrical connections between the ramps R. the armatures of thetrack relays 5, and the batteries 10 and 11, will not be described indetail, since these electrical connections and the different operatingcircuits will be fully set forth in the description of the operation.

The train is shown diagrammatically as comprising two pairs of wheels1212 and l414 connected by the usual axles 13 and 15; and the body orframe of the vehicle or of the separate cars or locomotives constitutinga train is represented by a bar 16 con nected to the axles 13 and 15. Acontact, shoe is carried by the train in any suitable way in position tocooperate with the ramps R, and is shown as mounted upon a bracket 17,which for simplicity is assumed to be made of some insulating materialand which is secured to the journal box or axle 15. Mounted on thebracket 17 is a vertically movable plunger or shoe 18 which is presseddownwardly by a spring 19. The shoe 18 is arranged in the same plane asthe ramps R and is designed to make electrical contact with said rampsas the train passes them. and also to actuate a suitable circuitcontrolling device. To accomplish this latter function. the shoe 18 isshown provided with an insulating button 20 which is arranged to lift a.contact spring 21 out of contact with a contact piece 22 when the shoe18 is raised.

The apparatus of the train control system carried on the train iscontrolled by a control relay 23 having three armatures 24, 25 and 26arranged to open and close certain controlling circuits hereinafter setforth. The energy for operating the apparatus on the train is derivedfrom a suitable source of current, as a battery 27, carri-ed by thetrain.

The means for establishing or determining the permissive speed for thetrain at the different points in its travel and the means fordetermining the actual speed of the train are operatively connected tothe wheels of the train, preferably to the axle of a pair of wheelswhich are neither driven nor braked. In the construction shown, abeveled gear 28 is keyed to the axle 15, and this beveled gear 28 mesheswith another beveled gear :19 fixed to a shaft 30, which is journaled insuitable supports 81. To the shaft 30 is secured a bifurcated member 32,and pivoted to the outer end of each of the bifurcations of saidmemberBQ is av weighted arm 33, which has secured thereto a toothedsector 84. Mounted loosely on the shaft 30 is a sleeve 35, which hasteeth 36 arranged and adapted to cooperate with the teeth of the sector34, and which isprovided with two collars 37, between which is mounted aloose collar or sleeve 88. An arm 39 is pivoted between its ends upon afixed pin or shaft- 40 and is pivotally secured at one of its end to thesleeve 38, the

extension of said arm 39 beyond its pivot axis being designated 39 Tothe end of the shaft 30 is fixed a bifurcated and an enlarged head 41,between which and the outer collar 37 is interposed a compression coilspring 42. Pivotally connected to the bifurcations of the head 41 is apin 43, which is pivotally connected to the forked ends of an auxiliaryshaft 44. The head 41 and the pin 43, together with the pivotalconnections between said parts, form a universal coupling for connectingthe shaft 30 and the auxiliary shaft 44.

Fixed to the auxiliary shaft 44 is a worm gear 45, and adjustablymounted on the outer end of said shaft 44 is a counterweight 46. Theauxiliary shaft 44 is arranged to be attracted upward by anelectromagnet 47, hereinafter termed the cam-starter magnet. A wormsector 48 is secured to a shaft 49 journaled in suitable bearings (notshown) in position to have its teeth cooperate with the teeth of thewornti gear 45, when the auxiliary shaft 44 is disengaged from thecam-starter magnet 47 and is in its lower position. The worm sector 48is formed with a laterally projecting sector 50 having abrupt shouldersat each end; and loosely journaled on the shaft 49 are two weighted arms51 positioned so as to engage the shoulders of the sector 50, fixedstops or rests 52 being arranged to limit the clownward movement of saidweight-ed arms 51. A cam 53 is secured to the shaft 49 so as to rotatetherewith in correspondence with the worm sector 48. The factorsdetermining the shape of the cam 53 will be pointed out hereinafter inthe description of the oper ation.

An arm 54 is journaled upon the shaft or pin 40 and carries at its upperend a roller 55, said arm 54 being arranged to swing in the same planeas the cam 53, so that in certain positions of the arm 54 the roller 55will engage the cam surface or edge of said cam 53. The arm 54 extendsbelow its pivot axis, the extension being designated 54 and secured inthe extension 39 of the arm 39 and in the extension 54 of the arm 54 aretwo contact pins 56 which are arranged to make electrical contact witheach other when the upper ends of the arms 39 and 54 are fully separatedby the spring 58, said pins 56 being insulated from the respectiveextensions 39 and 54 Also secured in and insulated from the extensions39 and 54 are two contact springs 57, which make contact with each otherwhen the upper ends of the arms 54 and 39 are fully separated, as shown,and also after said arms have been pressed together for a shortdistance.

In this automatic train control system it is assumed that the train orvehicle is equipped with the ordinary type of pneumatic brakes whichincludes the usual train pipe 61. The construction and operation of thepneumatic system of brakes is well known, and it is deemed unnecessaryto describe the construction and operation of this system in detail, itbeing sufficient for a clear understanding of this invention to knowthat the brakes are automatically applied on the train when the trainpipe 61 is vented. In the train pipe 61 is inserted a suitable valve(50, which is operated by a solenoid 59, said valve 60, in theparticular construction shown, being closed when the solenoid 59 isenergized and being opened by the pressure in the train pipe 61, aspring or other means when said solenoid 59 is deenergized. Theautomatic train control system is also preferably provided with awarning signal, which in this instance is shown as a whistle 62, whichis operated by compressed air supplied from the train pipe 61 through apipe 63. A suitable valve (not shown) is inserted in the pipe 63 tocontrol the communication between said pipe and the whistle 62, and thisvalve is designed to be operated by a suitable electromagnet 64, whichin the construction shown holds said valve closed when energized andpermits said valve to be opened by a spring or other means whendeenergized.

The worm sector 48 and the cam are moved to different positions by alever 65, which is pivoted at one end to a fixed pin 66, and ispivotally connected at its other end to a worm sector 48 by a pivotedlink 67. The lever 65 is operated by two soleloo noids'68 and 69; andthe core 70 of one of said solenoids 68 is pivotally connected to thelever near its pivot 66, the core 71 of the other solenoid 69 beingbifurcated at its upper end and straddling the lever 65 and beingprovided with a pin 72 extending across the bifurcations of said core'71 above. the lever 65. The pin 72 of the core 71 of the solenoid 69engages the lever 65 at a greater distance from its pivot 66 than thedistance between said pivot 66 and the pointof connection of the core ofthe solenoid 68 with said lever. Each of the solenoids 68 and 69 has apivoted armature 73 and 74. re-

spectively, which are shown according to established convention andwhich are raised to their upper position when said solenoids areenergized.

The selector comprises a suitable plate 75.

' which for simplicity is assumed .to be made of insulating material.and which is preferably supported upon the front axle 13 and is enclosedin a suitable easing. Mounted on the plate 75 are three plungers ortappets 5 76, 77 and 78, which extend through suitable guides 79 securedto or integral with the plate 75. a transverse pin 80 in each of saidplungers being arranged to engage the upper guide 79 for that plungerand thereby limit the downward movement of said plunger. A compressionspring 81 surrounds each plunger and bears at one end against a collar82 pinned thereto and at its other end against the upper guide 79. Theplungers 76. 77 and 78 have secured thereto contact pieces 83, 84 and85, respectively, which are positioned to cooperate and make electricalcontact with three pairs of contact springs 86-87, 88-89 and 9091,respectively. These pairs of contact springs are connected by suitableconductors to the solenoids 68 and 69, but these conductors, as well asthe other conductors connecting the different; parts of the traincontrol system carried on thetrain, will not be described in detail.since these conductors and the operating (l1 cuits will be set forthhereinafter in the description of the operation.

Operation: The parts of the apparatus carried on the train are shown inthe drawing in their normal positions. in which the trains may proceedunrestrained by the speed control apparatus. except for a limitationupon the maximum speed it may attain at any time, which is hereinafterexplained. Vhen the parts are in their normal positions, the controlrelay 23 is energized by current supplied from the local battery 27along a circuit, which may be traced as follows:

Circuit number one.

From the battery 27, conductors 92, 93

and 94, armature 24; of the control relay 23 in its upper position,conductors 95 and 96,

control relay 23, conductors 97 and 98, contact spring 20, contact piece22, and conductors 99 and 100 back to the battery 27.

hen the control relay 23 is energized and its armature 25 is in itsupper position, a proceed signal, which is shown as a green lamp G. isoperated by a circuit which may be traced as follows:

Cirmlif number two.

From the battery 27, conductors 92 and 101. armature 25 of the controlrelay 23 in its upper position, conductor 102, green lamp G, andcmiductors 103. 104, 10 106 and 100 back to the battery 27.

\Vhen the control relay 23 is energized and its armature 26 is in itsupper position, the cam starter magnet 47 is supplied with current fromthe battery 27 along a circuit which may be traced as follows:

Circuit number three.

From the battery 27, conductors 92, 93, 107. 108 and 109. cam startermagnet 17, conductor 110, armature 26 of the control relay 23 in itsupper position, and conductors 111, 106 and 100 back to the battery 27.

\Vhen the parts are in their normal positions the solenoid 59 whichcontrols the brake valve 60 is energized to hold said valve 60 closed.the circuit for said solenoid 59 being as follows:

Circuit number four.

Battery 27, conductors 92,93, 107, 108, 112, and 118. solenoid 59,conductor 119, contact springs 57 and conductors 120, 116, 117, 104,105, 106 and 100 back to the battery 27.

Also, when the parts are in their normal positions, the electromagnet 64for controlling the whistle 62 is energized. the circuit therefor beingtraced as follows:

Circuit member five.

From the battery 27. conductors 92, 93, 107, 108, 112 and 113.electromagnet 64. conductor 114, contact pins 56, and conductors 115,116, 117. 104, 105, 106 and 100 back to the battery.

llaving described generally the construction and arrangements of theparts of an automatic system for controlling the speed of railway trainsembodying the invention, and the controlling circuits for the apparatuson the train, the operation of the system as a whole will be describedfor a few cases in which certain trafiic conditions, such as may occurin practice, are assumed to exist.

For the first condition of traffic to be considered, assume that thetrain in question is at the end of the block A, and about to enter theblock B; that said train has found the trackway unobstructed and hasbeen running unrestrained by the speed control apparatus; and thatneither the blocks B nor C are occupied by another train. Since neitherthe blocks B nor are occupied by a train, their respective track relaysand 5 are energized from the corresponding track batteries a, and thearmatures of said track relays are in their upper positions, as shown.Whenthe shoe 18 of the train engages the ramp R, the shoe 18 is raisedand also makes electrical contact with said ramp. The raising of theshoe 18 pushes the coin tact spring 20 out of contact with the contactpiece 22 so as to interrupt the normally closed circuit number one forenergizing the control relay 23; and the electrical contact between theshoe 18 and the ramp R completes a circuit for energizing the controlrelay 23 which may be traced as follows:

Circuit number sz'a'. Commencing at the ramp R, conductor 121,

armature 8 of the track relay 5 in its upper position, conductor 122,battery 11, conductors 123 and 12 1, battery 10, conductor 125, trackrail 1, thence through the Wheels and axles to the frame 16, conductors126 and 96, control relay 23, and by conductors 97 and 12? to the shoe18 and back to the ramp R.

As the train proceeds and the first pair of wheels 12-12 and axle 18enter the block B, the track relay 5 is deenergized and its armature 8drops and interrupts the circuit number six. \Vhen the armature 8 of thetrack relay 5 drops another circuit for energizing the control relay isset up as follows:

Circuit om'mber seven.

Commencing at the ramp R, conductor 121, armature 8 of the track relay 5in its lower position, conductor 128, armature 9 of the track relay 5 inits upper position, conductors 129 and 122?, battery 10 conductor 125 tothe track rail 1, thence by the wheels and axle to the frame 16,conductors 126 and 96, control relay 23, and by conductors 97 and 12'?to the shoe 18 and back to the ramp R.

The armatures of the control relay 23 being raised, the sn'iall currentderived from the battery 10 alone is sufficient to hold said armaturesin their upper position. This characteristic of the control relay 23,whereby its armatures will not be raised when the sinall current derivedfrom the battery 10 alone flows through the coil of said relay, andwhereby the arinatures of said relay will be held in their raisedposition by this small current, may be obtained in a number of differentways, all well known in the art, and it is deemed unnecessary to showand describe the specific construction of the con trol relay 28. a

When the shoe 18 leaves engagement with the ramp R, it is forceddownward by its weight and the spring 19 to follow the gradual downwardslope of the end of the ramp it, so that the contact spring 20 remakescontact with the contact piece 22 before the shoe 18 leaves electricalcontact with the ramp, thereby reestablishing circuit number one beforecircuit number seven is broken.

From the foregoing it can be seen that when the train enters the blockB, and when the blocks B and C are not occupied by another train, theparts of the speed control apparatus on the train are not affected andremain in their normal position.

For the next condition of tratfic to be considered, assume that thetrain in questionis in the block A and about to enter the block B; thatthis train has found an unobstructed trackway and has been travelingunrestrained by the speed control apparatus; and that while the block Bis not occupied by another train, there is a train in the block C. Underthese conditions, while the track relay 5 of the block B is energized,the track relayo of the block C is deenergized. When the shoe 18 engagesthe ramp R and before the first pair of wheels and axle of the trainenter the block B, the circuit number six hereinbefore traced, will beestablished; but when the first pair of wheels and axle of the trainpass into the block 13, said circuit numher six is interrupted by thedeenergization of the track relay 5 and the dropping of its armature 8;and since the circuit number seven is interrupted by reason of the factthat the armature 9 of the track relay 5 is in its lower position, nocurrent is supplied from any of the batteries along the trackway to thecontrol relay 23. Also, the circuit number one for normally energizingthe control relay 23 is broken by reason oi the fact that the shoe 18 israised; and consequently the relay 23 is cut off from all sources of thesupply of current, and its armatures 24:, 25 and 26 drop.

The dropping of the armature 2d of the control relay 28 opens break inthe circuit number one, which normally energizes the control relay 23when the shoe 18 is in its normal or lower position, so that, when theshoe 18 leaves contact with the ramp It and returns to its lowerposition, nevertheless, the circuit number one Will not be reetablished. The dropping of the armature 25 breaks the circuit numbertwo, which causes the green lamp G to be lighted, and also closes acircuit for lighting the yellow lamp Y, said circuit being as follows:

Circuit number eight.

From the battery 27, conductors 92 and 101, armature 25 of the controlrelay 28 in its lower position, conductor 150, yellow lamp Y, andconductors 151, 105, 106 and 100 back to the battery 27. i

The dropping of the armature 26 of the control relay 23 interruptscircuit number three, which normally energizes the cam starter magnet47, and when the cam starter magnet 47 ceases to pull upon the auxiliaryshaft 44, the counterweight 46 on said shaft pulls said shaft to itslower position and rings the teeth of the worm gear 25 into mesh withthe teeth of the worm sector 48. The auxiliary shaft 44 is connected tothe axle 15 0f the vehicle or train, and as the train proceeds along thetrack the worm sector 48 and the cam 53 are turned in the directionindicated by the arrow X, the lefthand weighted arm 51 being lifted atthe same time.

The shape of the cam 53 is determined from the braking curve of thetrain which carries the cam, this braking curve, well known to thoseskilled in the art of braking trains, being found for each particulartype of train and braking equipment by calculations, actual tests andthe like. This braking curve of the train may be said to represent foreach speed of the train the distance required to bring the train to astop by its brakes; or, in other words, from the braking curve it ispossible to determine for each point in the travel of the train how fastthe train can be moving at that point and yet be brought to a stop byits brakes before another certain point is reached. In the particularkind of cam shown, the lengths of the radii of said cam representdifferent speeds, and the angular displacement of said cam representsdifferent distances traveled by the train; and in effect, the camrepresents a predetermined functional relation between the speed of thetrain and the distance traveled by the train. The effective action ofthe cam 53 takes place along the line of movement of its follower,namely, the roller 55 of the arm 54, which line of movement is the arcof a circle having its center at the axis of the shaft or pin 40 onwhich the arm 54 is journaled, this are of the line of movement of theroller 55 being indicated in the drawing by a dash line designated 1/.The radius of the cam 53 to the point where this are g intersects theedge of the cam, represents proportionately the permissive speed for thetrain at the point in its travel corresponding to the angulardisplacement of the cam at that instant. It is to be understood that thecam 53 will be of a different shape for different types of trains havingdifferent braking equipments; and that while the shape of the cam 53shown in the drawing illustrates in a general way the shape of apractical cam, it should be understood that the shape of the cam 53shown is not quantitatively precise.

The actual speed of the train is represented by the position of the arm39, which is shown in the drawing in its position of zero speed. As theshaft is turned by the axle of the train to which it is connected, theweighted arms 33 are thrown outwardly by centrifugal force and thecooperation of the teeth on the sector 34 fixed to these arms 33 withthe teeth 36 on the sleeve causes the sleeve 35 to move lengthwise ofthe shaft 30 against the opposition of the spring 42. The operation ofthe weighted arms 33, the sleeve 35 and the spring 42 is similar to thatof the well known centrifugal governor. As the sleeve moves, it carrieswith it the upper end of the arm 39, and the spring 58 between the arm39 and the arm 54 causes the arm 54 to take a corresponding movement.The parts are shown so proportioned that when the actual speed of thetrain, represented by the movement of the arms 39 and 54, is nearly asgreat as the permissive speed prescribed by the cam 53, the roller 55 ofthe arm 54 will touch the edge of the cam 53. As the cam 53 is turned bythe worm gear 45 and the worm sector 48 in the direction of the arrow X,the radii of the cam increases proportionately to the functionalrelation between the distance traveled by the train and the permissivespeed for the train, determined from the braking curve; and,consequently, the roller is forced toward the right by the edge of thecam 53. As the arm 54 is moved to the right by the cam 53, unless theactual speed of the train is reduced correspondingly so as to permit thearm 39 to move to the right the same amount, the spring 58 will becompressed and the lower extensions 54 and 39 of the respective arms 54and 39 will be moved farther apart. The first slight movement of theextensions 54 and 39 apart from each other, which will result if theactual speed of the train approaches closely to the permissive speed forthe train, draws the contact pins 56 out of contact with each other soas to break the circuit number five which normally energizes theelectromagnet 64 and which normally retains the warning signal orwhistle 62 inactive, thereby causing said warning signal to sound. Thesounding of the warning signal 62 informs the engineer or motorman ofthe train that the speed of the train is too high and that he shouldapply the brakes at once. If the engineer obeys the warning signal andreduces the speed of the train to a safe amount below the permissivespeed for the train prescribed by the cam 53, the arm 39 will move farenough to the right to permit the contact pins 56 to again contact witheach other, whereupon the circuit number live will be reestablished andthe whistle (32 will cease to sound, thus informing the engineer that hehas been successful in reducing the speed of his train to a safe speed.In this way, in a system embodying this invention, a warning signal issounded whenever the actual speed of the train approaches too near thesafe permissive speed for the train.

If the engineer should be incapacitated, or should carelessly fail toreduce the speed of his train in obedience to the warning signal, thearms 54 and 39 will be moved closer together and cause the lowerextensions 54 and 39 to move far enough apart to bring the contactsprings 57 out of contact with each other, thereby breaking the circuitnumber four which normally energizes the solenoid 59 and holds the valvein the train pipe (51 closed, so that said valve (30 is opened by thepressure in the train pipe or by a spring to vent the train pipe 61 andcause an automatic application of the brakes. Suitable means, which,being well known in the art, is not illustrated, is preferably employedto prevent the engineer or inotorman' from opposing the automaticapplication of the brakes, and this means may be arranged to prevent thebrakes from being released until the train is brought to an absolutestop, or this means may be arranged to permit the brakes to be releasedas soon as the actual speed of the train has fallen a certain amountbelow the permissive speed of the train.

From the foregoing it can be seen that when the train enters the blockB, while the block C is occupied by another train, certain effects areproduced. as follows: First, a caution signal, which in this instance isthe yellow lamp Y, is operated; second, a warning signal is sounded assoon as the actual speed of the train approaches close to the permissivespeed for the train; and third, if the warning signal is disregarded andthe actual speed of the train approaches too close to or exceeds thepermissive speed for the train, the brakes for the train are automatically applied. In any event, the train will be brought to a stop or to asafe low speed by the time it reaches the end of the block B, either bythe engineer or inotorman, or automatically by the train controlapparatus.

For the next condition of traffic to be con sidered, assume that thetrain in question is in the block B and has had its speed controlled bythe train control apparatus in the same way as hereinbefore described;and further assume that the other train which formerly occupied theblock C moves entirely from the block G into the block I) before thefollowing train reaches the end of the block 13. lVhen the shoe 18 ofthe fol lowing train contacts with the ramp R at the entrance to theblock C and before the first pair of wheels and axle of said followingtrain enter the block C. the two batteries 10 and 11 will energize thecontrol relay 23, although it is deenergized, becc use of a circuitnumber nine which can be easily traced by analogy to circuit number sixhereinbefore traced. The energization f the control relay E23 raises itsarmature 26 and reestablishes circuit number three 'ingly located alongthe trackway.

for the cam starter magnet 47; and the cam starter magnet 47, beingenergized, lifts the auxiliary shaft 4% and draws the worm gear 45 outof mesh with the worm sector 48, whereupon the weighted arm 51 returnsthe worm sector 48 and cam 53 to their normal positions. Thereafter,when the first pair of wheels and axle of the train enter the block C,the control relay 23 will be again deenergized by reason of the factthat another train occupies the block 1); and this deenergization of thecontrol relay 23 sets the cam 53 into operation again in the same manneras hereinbefore described. In this way, the cycle of operation of thetrain control apparatus is commenced again at the entrance to the blockC.

The parts of the system, the operation of which has been described, willwork satisfactorily for railways where the blocks are all of the samelength; but, as pointed out in the preliminary discussion, in practicethe different blocks of a railway vary in length. Obviously, a trainentering a long block need not commence to reduce its speed as soon asit would in entering a short block at the same speed, and if compelledto do so by the train control apparatus, the trainis unnecessarilydelayed. For this reason, suitable provision is made in the systemembodying this invention for moving the cam 53 to different positionsaccording to the different lengths of the blocks; and while thismovement of the cam 53 may be accomplished in various ways, in theparticular construction shown, the cam 53 is moved to differentpositions by selectively energizing the solenoids 68 and 69 byselectively operating the selector tappets or plungers 7 6 or 78 bymeans of selector ramps correspond' In the particular arrangement shown,the space be tween the track rails 1 and 2 is divided equally to furnishspace for three separate rows of selector ramps, the ramps in the rownearest the track rail 2 being designated SL, the selector ramps in themiddle row being designated SC, and the selector ramps in the rownearest the track rail 1 being designated SR. The particular location ofthe selector ramps in the length of the blocks will be discussed laterafter the operation of the selector ramps and corresponding parts on thetrain operated thereby is made clear. v

Assuming that a train is passing from the block B into the block 0 anddisregarding for the moment the action of the middle selector ramp SC atthe entrance to the block C, when the front axle 13 of the traincarrying the selector tappets 76, 77 and 78 passes the selector ramp SL,the corresponding selector tappet 76 is raised to bring the contactpiece 83 carried thereby into contact with the pair of contact springs86 and 87,

thereby completing a circuit for energizing the solenoid 68, as follows:

Circuit number ten.

Commencing at the battery 27, conductors 92, 93, 107, 130 and 131,contact spring 87, contact piece 83, contact spring 86, conductors 132and 133, solenoid 68, and conductors 134, 135, 117, 101, 105, c and 100back to the battery :27.

The energization of the solenoid 68 attracts its core 70 and swings thelever 65 downwardly, thereby moving the worm sector 48 and the cam 53 ina direction opposite to the direction indicated by the arrow X, therighthand weighted arm 51 being lifted at the same time. This movementof the cam 53 places it in position so that it will have to be turnedfarther before it indicates for the arm 54 a. zero or a low permissivespeed; and in this way, the cam-53 is made to correspond to a longerblock. When the solenoid 68 is energized, the armature 73 controlledthereby is raised to its upper position, thereby closing a circuit whichmaintains the solenoid 68 energized after the tappet 76 leavesengagement with the selector ramp SL and under the impulse of the spring81 moves downward and opens the circuit number ten here nbefore traced.This maintaining circuit for the solenoid 68 is as follows:

Circuit number eleven.

Commencing at the battery 27, conductors 92, 93, 107, 130 and 139,contact spring 88, contact piece 84 of the selector tappet 77, in thelower position of said tappet, contact spring 89, conductors 138 and137, armature 73 in its upper position, conductors 136, 133, solenoid 68and conductors 134, 135, 117, 104, 105, 106 and 100 back to the battery27.

Since it is assumed that a train occupies the block D, the cam startermagnet 47 will be deenergized in the same way as hereinbefore describedand the auxiliary shaft 41 will drop under the influence of thecounterweight -16 to bring the worm gear 45 into mesh with the wormsector -18, whereupon the cam 53 is moved in accordance with thedistance traveled by the train, and in the same way as hcreinbeforedescribed compels the speed of the train to be reduced so as to; bringthe train to a stop or to a safe ow speed before the train reaches theend of the block C. This movement of the cam 53 is made against theopposition of the solenoid 68, but this will ordinarily cause no damage:and, if desired. the maintaining circuit number eleven for the solenoid68 may be made dependent upon the movement of the auxiliary shaftl i, ina way which will be apparentto those skilled in the art of railwaysignaling, so that when said auxiliary shaft 44 drops, said maintainingcircuit: number eleven will be interrupted. In the arrangement shown,the maintaining circuit number eleven for the solenoid 68 is controlledby the middle selector tappet 77, and said solenoid 68 will remainenergized until the train passes the next middle selector ramp SC. Whenthe middle selector iappet 77 engages the middle selector ramp 5C, it islifted to move the contact piece 84 out of contact with the contactsprings 88 and 89, thereby interrupting the maintaining circuit numbereleven for the solenoid 68.

The same operation takes place as the train enters the block D, which isassumed to be longer than the block B, but not as long as the block C,and which corresponds to the position of the cam 53, to which it isoperated by the solenoid 69. When the train passes the selector ramp SR,the righthand selector tappet T8 lifted to bring the contact piececarried thereby into contact with the contact springs 90 and 91, therebyclosing a circuit for energizing the solenoid 69, which circuit may betraced as follows:

Circuit number twelve.

Commencing at the battery 27, conductors 92, 93, 107. 130 and 140,contact spring 90, contact piece 85, contact spring 91, conductors 1-11and 142, solenoid 69 and conductors 113, 35, 117, 104-, 105, 106 andback to the battery 27.

The maintaining circuit for the solenoid 69 is as follows:

Circuit number thirteen.

Commencing at the battery 27, conductors 92, 93, 107, 130 and 139,contact spring 88, contact piece 84, contact spring 89, conductors 138and 115, armature 74 in its upper position, conductors 141 and 1-12,solenoid 69, and conductors 113, 135, 117, 101, 105, 106 and 100 back tothe battery 27.

In the system embodying this invention, there is also a limitationimposed upon the maximum speed which the train may attain at any time,regardless of whether the train is proceeding under a clear proceedsignal or under a caution signal. This maximum speed limitation resultsby reason of the fact that when the cam 53 is stationary, the arm 51 maybe moved a certain distance toward the left by the arm 39 incorrcspomlence with the actual speed of the train before the roller 55strikes the edge of said cam: but if the arm 39 is moved further towardthe left because of an increase in the actual speed of the train. theextensions 39 and 51 will be moved apart, since the arm 54 is held fromfurther movement toward the left by the cam 53: and this movement of theextensions 39 and 51 apart from each other will cause a separation ofthe contact pins 56, thereby causing the sounding of the warning signal;and a. still further movement of said extensions apart from each other,corresponding to a further increase in the actual speed of. the train,will cause the contact springs 57 to separate andthe brakes to beautomatically applied; In this way, although the train-may be travelingunder a full proceed signahthe actual speed of the train cannot beincreased beyond a certain n'laximum speed prescribed by the cam 53 inthe position which it then occupies. It is apparent that by energizingeither the solenoid 68 or the solenoid 69 the position of the cam 53 maybe changed so as to change the maximum speedlimitation for the trainunder a proceed signal. Further, it is apparent that, for the purpose ofcontrolling the speed of a train under a proceed signal, suitablepermanently deenergized ramps may be placed at diiferent points alongthe trackway other than at the entrances to the blocks, as forinstanceatdangerous curves and the like, and these rampsowill cause thecam starter magnet at? to be deenergized and thereby set the cam 53 intomotion to require the. actual speed of the train to be reducedto acertain amount; and subsequently, when the train has traveled a distancesuch as to move the cam 53 to a position corre sponding to a safepermissive speed, permanently energized ramp may be placed which willeffect a re-energizat-ion of the control relay 23 and the release of thecam 58.

Certain factors dependent upon the peculiar characteristics of the traincontrolsystem shown and described'determine the location of the selectorramps; but it is to be understood that other arrangements of parts willmodify the particular location of the se lector ramps shown andhereinafter described.

lhe effect of the middle selector ramp SC is to break the maintainingcircuits numbers eleven and thirteen for the solenoids 68 and 69, sothat, unless the worm gear is in mesh with the worm sector 48, theweighted arms 51 return the cam 53 to its normal position. The effectofthe side selector ramps it and SL is to energize the corresponding;solenoid 68 or 69 so that, unless the worm gear 45 is in mesh with theworm'seetor i8, the cam 53 is shifted to a position to correspond. Itshould be noted that even if the worm gear 45 isin mesh with the wormsector d8, so as to prevent the energization of the solenoid 68 or fromactually moving the cam 53, either of'these solenoids 58 or 69, whenenergized, raises its armature 73 or 74', although its core may notmove, and this armature closes the circuits numbers eleven am thirteenfor maintaining said solenoid energized until" arelease of the cam 53per mits it to be effective to actually move the cam 53. Oneconsideration for the location of the middle selector ramp SCfor eachblock may be-that, by placing this middle selector ramp near the exitend? of that block, the selection set up when the train entered thatblock will be held while the train is trayeling through that block andwill serve to impose the proper maximum speed limitation required forthat block. In some cases, this maximum speed limitation may be too highfor the physical conditions existing in that block, and in such cases itmay be necessary to locate the middle selector ramp SC near the entranceend of the block so as to release the cam 53 and allow it to return toits normal position. or to an? other one of its operated positions whichmay be set up simultaneously.

Whether or not a particular selection of the position of the cam 53 isto be used for controlling the speed of the train is determined shortlyafter the first pair of wheels and axle of the train enter the nextblock, whereupon the control relay 23 is either deenergized or keptenergized according to the traffic conditions. The particular selectionof the cam, however, should preferably be set up sometime before thefirst. pair of wheels and axle of the train enter that block which fitsthat position of the cam, that is, before the control. relay 23 wouldbedeen; ergized, if traific conditions were such that it should bedeenergized'; otherwise, if the new selection is not made by this time,the deenergization of the control relay 23 would deenergize the camstarter magnet 47' and cause the worm gear l5 to drop into mesh with theworm sector 4L8 and prevent the movement of the cam 53 by the solenoid68 or 69.

In controlling the positions of the cam 53 fordifterent lengths ofblocks, it is considered preferable to place the selector ramps so thatthe following sequence of operation. will, in general, occur; first, themiddle selector ramp SC is arranged to cancel the preceding selection;and this middle selector ramp may be located any distance ahead of theentrance of the block in question, providing' that it is not ahead ofthe pointwhere the control relay 23 on the train would be deenergized asthe train entered the preceding block, if traffic conditions were suchthat said control relay should be deenergized. Second, the proper sideramp SR or SL for obtaining the selection desired is located at somepoint following the middle selector ramp, and ahead of the point wherethe control relay 23 on the train would be deenergized as the trainenters the following block, if traffic conditions were such that saidcontrol relay should be deenergized. In short, if the point in eachblock at which the control relay 23 is deenergized as the train entersthat block, providing traffic conditions are such as to require thedeenergization of said control relay, is called the imaginary entranceto that block, the middle selector SC and the side selectors SR and SLmay be located at any point between the imaginary entrances between twosucceeding blocks.

There are a number of factors which determine the exact location of theselector ramps in the length of the different blocks, but oneexamplewill serve to illustrate how the different location of the selectorramps may be used to obtain significant changes in the control of thespeed of the train, if desired. For instance assume the case where ashort block, as the block l3, having a low maximum speed limitation, fora train traveling under a proceed signal is followed by a longer block,as the block C, which has a higher maximum speed limitation; and furtherassume that the conditions in the short block B are such that the trainafter it has proceeded for a short distance into that'block B can attaina much higher speed with safety than is permitted by the maximum speedlimitation of that short block. Under these conditions it is apparentthat it is preferable to locate the middle selector ramp SC and thecorresponding side selector ramp SR or SL shortly beyond the entrance tothe short block B, so that the vehicle shortly after it passes saidentrance will be released from the lower maximum speed imposed by theposition of the cam 53 for the speed control in the short block B, andwill be allowed to accelerate to the higher maximum speed permitted bythe maximum speed limitation of the succeeding longer block C. Asanother advantage of this last described arrangement, it may be notedthat when a number of locomotives or motor cars, each equipped with theautomatic train control apparatus embodying this invention, are included in the same train, these locomotives or motor cars will pass theside selector ramp shortly beyond the entrance to the short block B,which is back far enough from the entrance to the longer block C as toordinarily prevent the locomotives or motor cars in the rear part of thetrain, which have their cams in the position for the lower maximumspeed, from unnecessarily delaying the movement of the train as a whole.

For another example illustratinghow the location of the selector rampscan be used to modify the control of the speed of the train,'assume thata long block, as the block C, having a high maximum speed limitation, isfollowed by a shorter block, as the block D, which has a lower maximumspeed limitation; and further assume that the train in question may passthrough the block C at unrestricted speed but must be brought to a stopor to a safe low speed by the time it reaches the end of the block D.Under these conditions the control of the train may be satisfactorilyand safely accomplished within the limits of the shorter block D only incase the train enters this shorter block D at a speed not in excess ofthe maximum speed limitation for this block D, since the maximum speedlimitation is automatically determined by the cam with reference to thelength of the block D and the braking conditions therein. For thisreason it is necessary to compel the speed of the train to be reduced tothe lower maximum speed limitation for the block D at some point furtherback than the entrance to the block D, and this may be accomplished bylocating the middle selector ramp SC in the block C so that itwillrelease the cam 53 and cause it to assume its normal position at asullicient distance from the end of the block C that the resultingimmediate application of the brakes would cause the speed of the trainto be reduced equal to or less than that of the maximum speed limitationin the block D. In this way, unless the operator of the vehiclevoluntarily reduces the speed of the train, while it passes through theblock C, ready to meet the conditions in block D, the speed of the trainwill be automatically reduced. A side selector ramp, as SR, may belocated in the longer block C in position to select the position of thecam 53 suitable for the block D at substantially the same time orsubsequently.

The cam 53 is preferably arranged so as to be normally in the positionsuitable for the shortest block and lowest maximum speed, so that afailure of the apparatus to cause a movement of the cam to its otheroperated positions, corresponding to longer blocks and higher maximumspeeds, will result in the train being controlled by the cam on the sideof safety. Obviously, the cam 53 may be moved to any number of positionsby providing additional solenoids, like the solenoid 68 and 69,additional selector tappets like tappets 7G and 78, and additional sideselector ramps. Also, other movements of the cam 53 other than a simplerotation may be made in cases where it is found that the curve of speedand distance represented by the cam may be modified in this way toapproximate more nearly the actual braking curve of the train underdifferent braking conditions. Also, while the automatic train controlsystem embodying this invention has been shown and described as designedto be operated by direct current, simple modifications, which will beapparent to those skilled in the art of railway signaling, may be madewhereby alternating current may be used for the operating medium. Also,although one of the track rails, namely the track rail 2. is shown asdivided into blocks by insulating joints 3, both track rails may bedivided into blocks, if desired; and in cases where it is founddesirable to use the track rails as a return for propulsion current,both track rails may be used as a return by conessence necting" suitableimpedance bonds, Well lrnovvnjin' the art, to, thetraclt rails ofadja'centvblooks. Various other modifications may be-madein theparticular construction and control circuits shown and described withoutdeparting from the invention or from the particular physical embodimentthereofshown; and various features may be combined Wit-l1 this systemWithoutdeparting from theinvention; as for instance, sev-QIiIl'lOCOHlOtZlVQS01"1110l301" cars each equipped with; the traincontrol apparatus, may be combined into a train and provided Withsuitable electrical connections whereby some or all o'fthe parts of'therespective traincontrol apparatus may be operated simultaneouslyAlthough I "have particularly described the constructionot'one physicalembodiment of my: invention, and explained the operation andprinciplethereof, nevertheless, I desire to have it understood-that theiorm'selected is merely illustrative, but does not exhaust the possiblephysical embodiments of the idea ofmeans: underlying my invention.

What: I claim as new; and desire to secure by Letters Patentof theUnited States, is:

1-. In a system torxautomatically controlling the speed ofrailwayvehicles, in combination: speed responsive means'on the vehicle operatedin accordance; With the actual speed thereof; permissive speed means onthe vehicle for establishing permissive speeds therefor and biased toassume a predetermined low speed initial condition; means selectivelycontrolled at predetermined points along the traclrfor causing saidpermissive speed means to assume any one of a plurality of'other'highspeed initial conditions; and means controlled by apredeterminedcooperation of said speed responsive means and said permissive speedmeans for controlling the movement of'said vehicle. I I

2. In a system tor v automatically controlling, the speed-of railwayvehicles, inconibination: a speed responsive device on the vehiclerespondingto the, actual speed'thereof; a movable cam forestablishing-permissive speeds for the vehicle and biased to assume apredetermined lllltlillPOSltlOl]; means gov ernedin accordance withtrafiic conditions along the track and operable to move said cam' incorrespondence With the distance travelled by the vehicle; meansselectively controlled atpredetermined points along the track for movingsaid cam to any one of a plurality of other initial positions; and meansresponsive to apredetermined cooperationotsaid speed responsive deviceand saidcam for controllingthe movement of said vehicle.

3. In a system for automatically controlling the speedo'lf railwayvehicles, in combination: a cam for establishing permissive speeds"for'theveliicle and movable from an existing initial position to imposedecreasing permissivespeeds'; means controlled; at fixed points alongthetrack for moving said cam'to any one of a plurality of differentinitial positions and thereby changing the maximum permissive speedestablished by saidcam; said cambeing biased to assumeits-initial'position corresponding to the lowcst maximum permissivespeed; and means for; retarding the movement of said vehicle when itsactual speed exceeds-the permissive speed prescribed by the position ofthe cam.

4; In a system. for automatically control ling the" speed of trainsonrailroad tracks divided intobloclrs having normally closed trackcircuits, in combination: automatic speed control apparatus on thevehicle including a unitary permissive speed means acting in conjunctionwith other elements to determine the various speeds at which the vehiclemay travel, said permissive speed means havingdifi'erent initialconditions determining ditlerent maximum speeds-for the vehicleand'a'lso being-adaptedcwhen set into operation to change gradually fromthe existing initial condition to successively lower speed conditions;means partlyon the vehicle and partly along the track for governing saidpermissive speed means toselect the initial condition therefor; andmeans partly on the vehicle and partly along the track controlled by thetrackcircuits of blocks for governing theoperation of said permissivespeed means.

5. In a system for automatically controlling thespeed ofrailwayvehicles, in combination; permissivespeed means for establishingpermissive speeds for the vehicle and having an initial maximum speedcondition which it constantly tends to assume; electromagnetic deviceslion causing said permissive speed means to'assume any one of aplurality of other initial maximum speed conditions; cooperating devicescarried by the vehicle and located along the track for selectivelycontrolling said-electromagnetic devices; and means for retarding: themovement of said vehicle When its actual speed exceeds the permissivespeedprescribed by said permissive speedmeans.

6. In a system for automatically controlling the speed of railwayvehicles, in combination: a permissive-speed cam; means for moving saidcam in accordance With the distance traveled by the vehicle; cooperatingdevices-carriech by the vehicle and located alongthe trackforcontrolling-said means in accordance with traiiic conditions; aplurality of'electroinagnetic devices for moving said-cam to differentinitial positions; a controlling-circuit for each of saidelectromagnetic devices; and means partly on the veliicle and partlyalongtlie-track for governingthe said circuits selectively.

till) 7. In a'system for automatically controlling the speed of railwayvehicles, in combination: means responding to the actual speed of thevehicle; a permissive speed cam biased to assume a predetermined initialposition; means operable to move said cam from its existing initialposition to successively lower speed positions in accordance with theprogress of the vehicle along the track; means responsive to apredetermined cooperation of said first mentioned means and saidpermissive speed cam for controlling the movement of the vehicle;electromagnetic devices for moving said cam to any one of a plurality ofother initial positions; and cooperating devices carried by the vehicleand located along the track for selectively controlling saidelectromagnetic devices.

8. In a system for automatically controlling the speed of railwayvehicles, in combination: automatic speed control apparatus on thevehicle including a permissive speed means adapted to assume diiferentinitial conditions determining difierent maximum permissive speeds forthe vehicle and also adapted when set into operation to change graduallyfrom an existing initial condition to successively lower speedconditions; means tending to cause said permissive speed means to assumea low speed initial condition; and means partly on the vehicle andpartly along the track for governing said permissive speed means tocause it to assume higher speed initial conditions at predeterminedpoints along the track.

9. In a system for automatically controlling the speed of trains onrailroad tracks divided into blocks each having a normally closed trackcircuit, in combination: automatic speed control apparatus on thevehicle including a permissive speed means adapted to assume differentinitial conditions determining difierent maximum permissive speeds forthe vehicle and also adapted when set into operation to change graduallyfrom the existing initial condition to successively lower speedconditions; means partly on the vehicle and partly along the track forgoverning said permissive speed means to select its initial condition;and means partly on the vehicle and partly along the track controlled bythe track circuits of the blocks for governing the operation of saidpermissive speed means.

10. In a system for automatically controlling the speed of railwaytrains on tracks divided into blocks of different lengths each having anormally closed track circuit, in combination: a unitary permissivespeed device on the vehicle adapted to assume different initialconditions corresponding to the different lengths of blocks; meansoperable at predetermined points along the track for governing the saiddevice to select the required initial condition thereof; and meansassociated with each block and responding to hicle; means operable tomove said cam from its existing initial position gradually tosuecessively lower speed positions in accordance with the progress ofthe vehicle along the track; trackway devices for selecting the initialposition of said cam; and other trackway devices responsive to trallicconditions in the blocks for governing the operation of said means.

12. In a system for automatically controlling the speed of railwayvehicles, in combination; automatic speed control apparatus on thevehicle including a movable cam adapted to assume any one of a pluralityof different initial positions, said cam being biased to assume itslowest speed initial position; and means partly on the vehicle andpartly along the track for automatically and selectively moving said camto its higher speed initial positions.

13. In a system for automatically controlling the speed of railwayvehicles, in combination: automatic speed control apparatus on thevehicle including a unitary permissive speed element adapted to assumeditlen ent initial conditions; means tending to cause said permissivespeed element to assume a predetermined maximum speed initial condition;a number of electromagnetic devices each operable to cause saidpermissive speed element to assume a distinctive initial conditiondifl'erent than said predetermined maximum initial condition; circuitsfor controlling said devices; and means partly on the vehicle and partlyalong the track for selectively controlling said circuits.

14. In an automatic train control system "for railroads having tracksdivided into blocks of different lengths each provided with a normallyclosed track circuit, automatic speed control apparatus on a railwayvehicle including a permissive speed element adapted to change graduallyfrom a maximum permissive speed condition to an ultimate minimum speedcondition during the progress of the vehicle through a block, meanstending to cause said element to assume an initial maximum speedcondition corresponding to a short block, means effective atpredetermined points with reference to the entrance to longer blocks forcausing said element to assume higher maximum speed conditionscorresponding to the length of such blocks, and means controlled by thetrack circuits of said blocks for causing said permissive speed elementto commence its gradual change from itsthen existing maxi mum speedcondition at the entrance to each block when the neXt block in advanceis occupied.

15. in an automatic train control system for railroads having tracksdivided into bloclrs each provided with a normally closed track circuit,automatic speed control apparatus on a railway vehicle including a permissive speed device having a plurality of initial maximum speedconditions and adapted to change from its existing initial condi: tionand impose lower permissive speeds at successive points in the progressof the vehicle through a block, means effective to adjust said devicequickly to any one oi its initial maximum speed conditions, and meanspartly on the vehicle and partly along the track for governing saidmeans to selectively determine the initial condition to be assumed bysaid permissive speed device.

16. in an automatic train control system for railroads having tracksdivided into blocks of difi'erent lengths each provided with a normallyclosed track circuit, speed control apparatus on a railway vehicleincluding a permissive speed device capable of operating to imposepermissive speeds for the vehicle varying from a maximum to a minimum,said device having a tendency to impose an intermediate permissivespeed, means for adjusting said device to impose permissive speedshigher than said intermediate permissive speed, and means adapted to begoverned in accordance with trailic conditions for governing theoperaion of said device.

17. in an automatic train control system tor railroads having tracksdivided into blocks each provided with a normally closed track circuit,speed control apparatus on a railway vehicle including'aspeed-responsive device governed by the actual speed of the vehicle, achangeable permissive speed element adapted when set into operation tochange from its existing initial condition and establish decreasinglimiting permissive speeds for the vehicle, electro-responsive means onthe vehicle adapted to be influenced by trackway devices for quicklyadjusting said permissive speed element to any one of a plurality ofdiiferent initial conditions, and brake controlling means governedjointly by said speed-responsive device and said permissive speedelement.

18. in an automatic train. control system for railroads having tracksdivided into blocks each provided with a normally closed track circuit,speed control apparatus on a railway vehicle including aspeed-responsive device governed by the actual speed thereof, achangeable permissive speed element capable of assuming differentinitial conditions and adapted when set into op eration to changegradually during the progress 01' the vehicle and establish decreasinglimiting permissive speeds for the vehicle, electro-responsive'means onthe vehicle adapted to be influenced by trackway devices for quicklyadjusting said element to anyone of a plurality of diiierent initialconditions, a warning signal arranged to give an arrestive indication tothe operator of the vehicle, a brake setting appliance, and meansresponsive jointly to said speed-responsive device and said permissivespeed element for operating said warning signal and said brake settingappliance with an intervening interval of delay.

19. In an automatic train control sys: tem for railroads having tracksdivided into blocks of different lengths each provided with a normallyclosed track circuit, automatic speed control apparatus on a railwayvehicle including a movable cam for establishing various permissivespeeds for the vehicle and adapted to assume any one of a plurality oidifferent initial positions, control means on the vehicle adapted to beinfluenced by traiiic controlled trackway devices for causing said camto be gradually moved by the wheels of the vehicle from its existinginitial position and thereby estab lish gradually decreasing permissivespeeds, and other means partly on the vehicle and partly along the trackfor shifting said cam at a predetermined point with reference to theentrance to each block to an initial position corresponding with thelength of that block.

20. In an automatic train control system, speed control apparatus forrailway vehicles including a movable permissive speed element, mechanismfor shifting said element to different positions comprising a pluralityof electro-magnets operatively connected to said element and eachadapted to move it to a predetermined position, pickup and stickcircuits for said electromagnets, and means adapted to be intluenced bytraclrway devices for selectively controlling said circuits.

21. In combination, a railway vehicle, ve-

hicle controlling means thereon, means on the vehicle for controllingsaid vehicle controlling means comprising a speedcontrolled means and aspeed limit cam capable of being set for any one of a plurality ofspeeds, means spaced along the trackway for setting said speed limit camfor a determined speed, and other means along the t-rackway foroperating said speed limit cam in accordance with tralllc conditionsahead.

winrinnor K. HOWE.

